Creating a function to output factorials.

Hi I am trying to create a user defined function that will allow me to enter an integer and it will output the given factorial.

function [y] = fact(x)

clc
y=1;
for i=1:x
    y=y*i;
end
disp(y)

This is it and it is working but I also need it to display an error message if it is a negative integer or non integer (e.g 8.5) and for it to also display 1 for factorial 0.

I have tried adding if statements in the loop for if x<0 etc. but I am getting the same answer which is just 1.

It works for positive integers just not the others.

Any thoughts?

Answer 1

[Walter Roberson]

if ~isnumeric(x) || ~isscalar(x) || x ~= fix(x)     %x == fix(x) checks for integer
    error('Oh, oh, oh, oh, oh!')
end

[MILLER BIGGELAAR]

I am sorry but when fact(-x) (when x is a negative integer) i still receive the answer of 1 and not error, I have tried adding || x<0 after the if statement but this has not worked.

[Walter Roberson]

Works for me:

if ~isnumeric(x) || ~isscalar(x) || x ~= fix(x) || x<0     %x == fix(x) checks for integer
error('Oh, oh, oh, oh, oh!')
end

[MILLER BIGGELAAR]

I got it to work, I put the if statement after the factorial when I needed to put it before.

Much appreciated.